The plastic button probably got knocked out of place and can't hit the switch to power on/off (wow, way to get technical, eh? ).

You can just pull the power cord out of the back of the console every time you want to shut it off...or take the casing off and see what the problem is (and hopefully try to see the problem and fix it)

Do you have a multimeter? check that there is continuity across the little tactile switch when you press it. There are four connections, two on one side will be shorted together internally, same as the other side. Find two opposite sides that are open circuit, then press the button. Check the PCB trace on the PCB the switch is on, and also the cables. From memory it just brings a wire to ground when you press the button, and maybe the ground isn't connected, ie. "floating ground" which may be why you can turn it on but not off? Hard to know for sure without looking at it. :/
- Adam

Alrite,
am playing around with it(with the wire)
Before it was turning on itself when power was pluged in, now its not turning on itself anymore, but still the small button is not working.
Let me try again.

edit:
Is it possible to extend the wires connected to the dvd drive? I want to place it in my PC´s tower, as it has a free space, so I can leave my PC and xbox+game cube in the same place.

The plastic button probably got knocked out of place and can't hit the switch to power on/off (wow, way to get technical, eh? ).

You can just pull the power cord out of the back of the console every time you want to shut it off...or take the casing off and see what the problem is (and hopefully try to see the problem and fix it)

Click to expand...

His house can catch on fire if he repeats. Or the power thing will soon black out.

The plastic button probably got knocked out of place and can't hit the switch to power on/off (wow, way to get technical, eh? ).

You can just pull the power cord out of the back of the console every time you want to shut it off...or take the casing off and see what the problem is (and hopefully try to see the problem and fix it)

Click to expand...

Ya, this happened to like all of the appliances/ electronics at my house because my brother tries to put like his whole mass in pushing buttons... Seriously on the computer monitor only the Brightness + button still works, and on our TV only the Volume - and Channel + buttons work w/o the remote.

I've seen my share of this problem it can be several problem and most of them aren't related to the power on button.

Most of the time its the interal PSU that for some reason always pass on current it can also be the whole power handling circut on the MOBO but if it was you would have probably seen some artifacts of this/some of the internal ICs would have blown up.